1. Field of the Invention
The present invention relates to a display device and a manufacturing method thereof, and more particularly to a liquid crystal display (LCD) panel, a color filter, and a manufacturing method thereof.
2. Description of Related Art
Generally, in a manufacturing method of color filter for a common LCD, RGB photo resists are adopted to be processed by three photolithography processes, and three color photo resist films are sequentially formed in pixels on a substrate, thereby forming a color filter. The color photo resist films are formed by dripping the photo resist liquid on the substrate and then spin-coating the photo resist liquid on the substrate uniformly. As a result, most of the color photo resist is wasted during the spin-coating process, and furthermore, the photo resist is expensive, thereby causing a high manufacturing cost. In addition, the adopted photolithography processes require plenty of organic solvent, which possibly causes environmental contamination.
Recently, a method of forming a color filter by using an inkjet printing (IJP) process has been developed. The method includes the following steps, firstly, forming a black matrix with a plurality of openings on a substrate; then, dripping color pigments (red, green, and blue) into the openings of the black matrix by using an inkjet print head; and then performing a thermal baking process to cure the pigments, thereby forming a color filter. The inkjet printing method can simultaneously inkjet print RGB filter films in pixels, and significantly save the manufacturing processes and the material cost compared with the conventional photolithography processes adopted in manufacturing the color filter, so that the inkjet printing technology has an advantage of being manufactured in a large area.
Generally speaking, when the color filter is manufactured by using the inkjet printing technology, it is expected that all color pigments are dripped completely in pixel regions, so as to prevent the color pigments from overflowing or being mixed with each other. Therefore, the conventional process of dripping the color pigments in a pixel region requires that the positions of the first drop and the last drop of the color pigments in a pixel region are kept a certain distance away from the edge of the pixel region. In this manner, if the position where the color pigment is dripped is slightly inaccurate, the color pigment may be prevented from overflowing the pixel region to be mixed with other pigments. However, although such an inkjet printing method is capable of preventing the color pigments from overflowing or being mixed with other pigments, if the pixel region has a poor hydrophile property or the pixel region is too large, the unfilled phenomenon of the color pigment possibly occurs at the corners of the pixel region, and as a result, an LCD panel has a poor color saturation and poor displaying quality.